+1 the last sentence should read: not all rendering should go through the same view/projection transformation, one can even switch between perspective and orthogonal view in the same render tick
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Maik SemderJul 30 '11 at 10:31

3

@Maik Semder good point on noting the switch to orthogonal, which is likely to be what the OP needs for a UI.
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jv42Jul 31 '11 at 11:05

In SFML terms, you should be changing the active sf::View on your RenderTarget between rendering the world and the GUI. Your world View should be whatever is most convenient for your world rendering and centered on your player position; your UI View should be pixels or some standard resolution, rooted at the origin.